Improvement in locks



m @i @Vnwngs IMPROVE D Flat vKevf n Tumbler j.. Lock. NQ'. 118,986. Patented Sep. 12,1871.

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d/WO/@zxmf v w@ M Hlm UNITED STATES PATENT OEEIoE.

HENRY R. TOWNE, OF STAMFORD, CONNECTICUT.

IMPROVEMENT IN LocKs.

To all whom t may concern:

Beitknown thatI, HENRY R. TOWNE, of Stamford, in the county of Fairfield and State of Connecticut, have invented a new and useful Method of Constructing Flat-Keyed Tumbler-Locks 5 and I do hereby declare that the following is a .full and exact description thereof, reference being had to the accompanying drawing making a part of this specication.

The object of my invention is to produce a tumbler-lock of the ordinary form, arranged so as to be operated by means of a perfectly-flat wing key, which shall possess great simplicity and cheapness of construction. Many attempts have of late years been made to accomplish this end, but in no lock with which I am acquainted is it compassed by such simple, cheap, and yet efcacious means as in that herein described. In all locks of this kind `heretofore made the desired end has been attained in one oi'two ways, viz.: First, by the use otl a compound key, e., one, the body of which is iat, but which, by the addition of another piece or pieces, is made round at its lower end, where it enters the lock and is thus supported in its keyhole in the usual manner. Second, by the use of a perfectly-flat key, which is supported when in the lock by means of a suitably-termed rollback. The lirst or' these methods necessitates the use ot a very expensive form of key, and is, at the same time, in some measure a departure from the fiatkey style of lock sought to be obtained. The second methodis one necessitating the use of an expensive and more or less complicated roll-back in the lock, and which, in some of its forms, necessitates, also, a very undesirable weakening ot' the key.

The construction of my lock, however, is such that, while admit-ting of the use of a perfectlyiiat key, it requires no addition to the usual number of parts composing an ordinary tumbler-lock, save that of a roll-back of the most simple and inexpensive form, the key when in the lock being by no means entirely dependent upon this roll-back for its support.

In the annexed drawing', representing an ordinary three-tumbler mortise-lock, Figure l is a front elevation with the cover removed. Fig. 2 is a transverse section on line a b. Fig. 3 is a plan and edge view of the key. Fig. 4 is a side and end elevation of roll-back.

Similar letters of reference indicate corresponding parts throughout.

A is the case of the lock. the cover.

B is the bolt. C is I) is the front or face-plate. are the tumblers. F is the roll-back. G is the key. H is the lower key-guide. I I are the two supporting-rims, 011e on the case and one on the cover.

Upon the insertion ot' the key in the lock it is supported, during its entrance, laterally by the rollback F, and vertically by the keyguide H. If the key be revolved the two supporting-rims I I enter the corresponding notches K K in the key, and, the roll-back forming the lateral guide, the key is thus firmly supported during the whole of its revolution until returned to its original position.

It will be seen that the roll-back is flattened oft on its upper part, and that the tumblers bear upon it here, thus preventing it from being jarred around, and holding it always in proper position for the entrance of the key. This roll-back, it will also be noticed, is formed of a piece of common wire turned down on the ends, with the keyway sawed through it, thus requiring a minimum amount of material and labor in its construction.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

The combination of a i'lat metallic key having supporting-notches K K with a lock provided with the key-guide H and annular supportingrims I I, the combination of said features serving to 'furnish a continuous support for the dat key during the whole of its revolution.

HENRY R. TOWNE.

Witnesses:

A. W. RrcHARDs, E. T. GREENE.

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